Feature #17525: Implement Happy Eyeballs Version 2 (RFC8305) in Socket.tcp

• Status: Open
• Priority: Normal
• Assignee: Glass_saga (Masaki Matsushita)
• Target version: 3.1

[Glass_saga (Masaki Matsushita)]

https://github.com/ruby/ruby/pull/4038

This change implements Happy Eyeballs Version 2 (RFC8305) in Socket.tcp.
It enables fallback from IPv6 to IPv4 without a long waiting time.

[Glass_saga (Masaki Matsushita)]

• Related to Feature #15628: init_inetsock_internal should fallback to IPv4 if IPv6 is unreachable added